A container for preparing mixtures form two chemically interracting components, specifically a liquid and a powdery component, is known from German Auslegeschrift 1,287,251. The known container has two chambers which in its storage condition are sealed with respect to each other, each chamber holding one of the two components. For initiating the mixing process, a separating sheet provided between the two chambers is ruptured by pressure exerted on the liquid chamber, and continued pressure will displace the liquid from its chamber and transfer it to the chamber containing the powder where the mixing step proper is carried out by shaking the container.
Similar mixing containers are known from German Offenlegungsschriften 1,939,316, 2,009,403, 2,060,626 and 3,545,614.
U.S. Pat. No. 3,370,754 and German Offenlegungsschrift 3,715,682 disclose further devices in the form of two-chamber containers for mixing and dispensing substances, in which the partitioning between the chambers includes a valve element disposed in the wall of the mixing chamber.
Other mixing and dispensing devices for two-component substances are known from U.S. Pat. Nos. 3,885,710, 3,699,961, and 3,477,431. Each of these containers again includes some type of valve means for separating the two components in the storage condition.
The manufacturer provides the components in such quantities that the mixed substance exhibits optimum properties. If the mixing ratio is altered, these properties are deteriorated. This chance is not excluded with the known containers in view of the risk that an uncomplete reduction of the volume of the liquid chamber will result in the liquid being incompletely displaced into the mixing chamber or allow part of the liquid to flow back, during the mixing step, into the still existing volume of the liquid chamber.
A further problem with the known mixing containers resides in the fact that portions of the separating sheet may be included into the mixed substance.